Once daily Theo-Dur in morning dippers.

In a group of 18 patients with a so-called "morning dip", one single dose of theophylline was administered at 10:00 p.m. by means of a sustained release formulation (Theodur Retard). The dosage of theophylline was adjusted according to the complaints of the patients. Plasma theophylline levels were determined at 10:00 a.m. to prevent theophylline intoxications. The results were objectivated by measuring the PEFR twice/day. When the optimal dosage was obtained, a once/day administration of Theodur Retard at 10:00 p.m. provided an improved peak flow in the early morning, less symptoms at night and a better quality of sleep.